Fugu Ultra v2 vs GLM 5.3 Flash
Pricing, context window and real answers (September 2026)
Fugu Ultra v2 (Sakana AI) and GLM 5.3 Flash (Z.ai), compared as you can actually call them on FastMetal. Both are served from the same OpenAI-compatible endpoint and API key; switching is a change to the model string.
Specs and pricing
| Fugu Ultra v2 |  GLM 5.3 Flash | |
|---|---|---|
| Provider | Sakana AI | Z.ai |
| Input (per 1M tokens) | ¥893.5 | ¥26.81 |
| Output (per 1M tokens) | ¥5,361 | ¥89.35 |
| Typical cost (1,000 in + 500 out tokens × 1,000 calls) | ¥3,574 | ¥71 |
| Context window | 1,000,000 tokens | 1,310,720 tokens |
| Release date | 9/11/2026 | 8/26/2026 |
| Input modalities | text, image, file | text, image, video |
| Throughput (p50) | — | — |
| Arena · overall | Unranked | #29 · ELO 1,475 |
| Arena · Japanese | Unranked | #51 · ELO 1,427 |
| Arena · coding | Unranked | #20 · ELO 1,525 |
Prices are FastMetal's yen rates before tax. Arena ranks are as of the latest leaderboard scrape.
Which should you pick?
- On price, GLM 5.3 Flash: ¥89.35 per 1M output tokens, 98% less than Fugu Ultra v2.
- For long documents, GLM 5.3 Flash: a 1,310,720-token context window against 1,000,000 for Fugu Ultra v2.
- If in doubt, try both on the same key. Switching is a change to the model string, and each is billed at its own rate.
Real answers to the same prompts
Exactly what the FastMetal gateway returned, side by side. Not benchmark scores: actual output.
Count the number of 'r's in 'strawberry'
Count the number of 'r's in 'strawberry'. Explain your reasoning step by step.
Fugu Ultra v2
**Answer: 3**
**Step-by-step reasoning:**
1. **Write out the word letter by letter**, assigning each a position:
| Position | Letter | Is it 'r'? |
|---|---|---|
| 1 | s | no |
| 2 | t | no |
| 3 | **r** | ✅ yes |
| 4 | a | no |
| 5 | w | no |
| 6 | b | no |
| 7 | e | no |
| 8 | **r** | ✅ yes |
| 9 | **r** | ✅ yes |
| 10 | y | no |
2. **Tally the matches:** positions 3, 8, and 9 are 'r'.
3. **Sanity check by chunks:** "straw" contains one 'r' (str**a**w → the r in "str"), and "berry" contains two 'r's (be**rr**y). 1 + 2 = 3.
4. **Verify length:** the letters counted total 10, which matches the length of "strawberry" — so no letter was skipped or double-counted.
**Conclusion:** There a…
10.2s435 output tokens
GLM 5.3 Flash
# Counting 'r's in 'strawberry'
**Step 1: Write out the word letter by letter**
s - t - r - a - w - b - e - r - r - y
**Step 2: Check each letter one at a time**
| Position | Letter | Is it 'r'? |
|----------|--------|-----------|
| 1 | s | No |
| 2 | t | No |
| 3 | r | **Yes! (1)** |
| 4 | a | No |
| 5 | w | No |
| 6 | b | No |
| 7 | e | No |
| 8 | r | **Yes! (2)** |
| 9 | r | **Yes! (3)** |
| 10 | y | No |
**Step 3: Add up the matches**
The 'r's appear at positions 3, 8, and 9.
## Answer: There are **3** 'r's in "strawberry" 🍓
7.2s449 output tokens
Debug This Error
I'm getting the following error in my Node.js application: TypeError: Cannot read properties of undefined (reading 'map') at UserList (/app/components/UserList.js:12:25) at renderWithHooks (/app/node_modules/rea…
Fugu Ultra v2
## What the error means
`TypeError: Cannot read properties of undefined (reading 'map')` means that when `UserList` rendered, `users` was `undefined`, and JavaScript can't read the `.map` property off `undefined`.
The important detail: **the bug isn't really in `UserList`** — that's just where it surfaces. Destructuring `function UserList({ users })` does *not* throw when the prop is missing; it silently gives you `undefined`. The crash is deferred to the first property access, which is `.map` on line 12.
So the real question is: why is `props.users` not an array?
## Why `users` is undefined
**1. Async data hasn't arrived yet — by far the most common cause.**
```jsx
const [users, setUs…
70.8s5286 output tokens
GLM 5.3 Flash
## What's happening
The error means the `users` prop is `undefined` at the time `UserList` renders. Since you can't call `.map()` on `undefined`, JavaScript throws the TypeError.
This usually happens for one of these reasons:
1. **The parent isn't passing the prop** — rendering `<UserList />` without `users`, or with a typo'd prop name like `user={users}`.
2. **Data hasn't loaded yet** — the parent fetches data asynchronously and its state starts as `undefined`:
```jsx
const [users, setUsers] = useState(); // undefined until fetch resolves!
return <UserList users={users} />;
```
3. **API response shape mismatch** — the array is nested, e.g., you need `response.data.users` inst…
31.3s1639 output tokens
Code Review
Please review the following Python function and suggest improvements for readability, performance, and best practices: def get_data(url, retries=3): import requests import time for i in range(retries):…
Fugu Ultra v2
# Final Code Review: `get_data`
The function is compact and its intent is clear, but as written it will **fail silently in production**. Two defects dominate everything else:
1. The bare `except:` swallows every error — including `KeyboardInterrupt` and genuine logic bugs.
2. A total failure and a legitimately empty dataset both return `[]`, so callers cannot tell "the service is down" from "there are no active records."
Together these mean an outage looks exactly like a successful empty response. Everything else below is meaningful improvement; those two are the difference between code that fails loudly and code that fails invisibly.
---
## 1. Correctness and error handling
### 1.1 `e…
281.1s23317 output tokens
GLM 5.3 Flash
Solid foundation — you're already passing an explicit `timeout` and implementing retries, which many people skip. Here's a breakdown by category:
## Correctness & robustness (most important)
- **Bare `except:`** catches *everything*, including `KeyboardInterrupt` and `SystemExit`, and silently discards the error. Catch specific exceptions: `requests.RequestException` for network issues, `ValueError` for invalid JSON.
- **Retrying non-retryable failures**: a 401/403/404 will never succeed on retry, so you're sleeping 6 seconds for nothing. Only retry transient errors (5xx, 429, timeouts/connection errors).
- **`item["active"]` raises `KeyError`** on malformed data. Use `item.get("active")`…
116.1s6185 output tokens
Frequently asked questions
- Which is cheaper, Fugu Ultra v2 or GLM 5.3 Flash?
- Per 1M output tokens, Fugu Ultra v2 is ¥5,361 and GLM 5.3 Flash is ¥89.35 on FastMetal (yen, before tax), so GLM 5.3 Flash is cheaper.
- How do the context windows of Fugu Ultra v2 and GLM 5.3 Flash compare?
- Fugu Ultra v2 takes 1,000,000 tokens; GLM 5.3 Flash takes 1,310,720.
- Can I use Fugu Ultra v2 and GLM 5.3 Flash with the same API key?
- Yes. On FastMetal's OpenAI-compatible endpoint, switch by passing "fugu-ultra-v2" or "glm-5.3-flash" as the model. Each is billed at its own rate from the same prepaid balance.
Try both on one API key
Create an account and add credit to call Fugu Ultra v2 and GLM 5.3 Flash from the browser chat and the API. No monthly fee.